Hydraulic vane pumps are used to pump hydraulic fluid in many different types of machines for different purposes. Such machines include, for example, transportation vehicles, agricultural machines, industrial machines, and marine vehicles (e.g., trawlers).
Hydraulic vane pumps are usually coupled to a drive, such as to a rotating output shaft of a motor or an engine and, it the absence of expensive space invasive clutches or other disconnecting means, continue to pump hydraulic fluid as long as the motor or engine continues to operate. A rotor of the pump usually has a rotational speed determined by the rotational speed of the motor or engine.
One known limit to improving the pressure and speed Capability of vane pumps is the out-of-balance forces applied to the under-vane regions in the mid quadrant. In this regard, hydraulic vane pumps typically have an inlet located at the start of the rise region. The inlets supply low pressure hydraulic fluid to the rise region. As the vanes move the oil through the rise region, into the major dwell and then into the fall region, the oil becomes pressurized. The pressurized oil leaves via outlets associated with each fall region of the pump.
Rotary couplings are also utilized in transportation vehicles, industrial machines, and agricultural machines to transmit rotating mechanical power. For example, they have been used in automobile transmissions as an alternative to a mechanical clutch. Use of rotary couplings is also widespread in applications where variable speed operation and controlled start-up without shock loading of the power transmission system is desired.
My currently pending application U.S. patent application Ser. No. 13/510,643, describes a hydraulically controllable coupling configured to couple a rotating input to an output to rotate. The coupling can also decouple the input from the output by switching the hydraulic device such as a vane pump between a pumping mode and a mode in which it does not pump. Currently pending application U.S. Patent Application Ser. No. 62/104,975 also describes systems and methods using a plurality of hydraulic devices each configured to be operable as a hydraulic coupling and as a vane pump.